German Patent No. 1,196,193 dated July 8, 1965 discloses the alkylation of a 17.beta.-acyloxy-3,5-diketo-4,5-seco-19-nor-.DELTA..sup.9 -androstene, which is selectively ketalized in the 3-position, by means of a lower molecular weight alkylation agent in the presence of an alkali metal tert.-alcoholate to yield in a stereospecific reaction only the corresponding 10.beta.-compound.
A subsequent study [J. E. McMurry, Ph.D. Thesis, Columbia University, New York, (1967)] was unable to confirm this statement. On the contrary, under various reaction conditions, including those given in the aforementioned Patent Specification, there was obtained a mixture of 10.beta.:10.alpha.-compounds in the proportion 2:1.